Prop-1 Trainer & Prop-2 - TIP

[ilusion]

A quick tip for those of you just starting to play with Prop-2 units. :)

I noticed something when I went to install my Prop-1 Trainder board onto my Prop-2. If you place the trainer on pins 0-7 (rather than using the 8-15 pins) you need to look carefully to make sure you are not shorting the pins on the 3 pin header of the Pro-1 trainer,  to the top of the electrolytic cap on the Prop-2.

I caught this before I powered up the board, and though I dont have a schematic here to verify, I can imagine if the top of the cap is gnd (or v+ for that matter) it would have been possible to cause a direct short if the pins on the bottom side of the Prop-1 trainer board had come into contact with the top of the cap!

I relocated the trainer board to pins 8-15 to avoid this possible issue. However, it might be posible to use the trainer board on the lower set of pins if you were to make sure a good insulator was placed between those pins and the top of the cap.

Its a good idea to take a careful look at your connections before applying power!  ;D

[JonnyMac]

We are in fact looking at relocating the 5 VDC caps (for filtering when servos are connected) so that the Prop-1 Trainer can be used on P0..P7 pins.  Typically, however, we would use it on the upper group as P14 has a SETUP jumper which corresponds to the button input circuit on the Prop-1 Trainer.

To use the potentiometer circuit on the P1T you need to use a bit of code as that circuit is constructed for the Prop-1.  Here's a subroutine I've used:

' Reads POT circuitry from Prop-1 Trainer Board
' - "PotPin" will be 15 (recommended) or 7 (not recommended for Rev A Prop-2 boards)

Get_Pot:
  HIGH PotPin                                   ' charge cap
  PAUSE 1                                       ' 5 x R (220 ohms) x C (0.1 uF)
  potVal = 0                                    ' clear output value
  DO
    LOW PotPin                                  ' discharge cap a bit
    INPUT PotPin                                ' set to check level
    IF (PotPin = 0) THEN EXIT                   ' stop at threshold
    potVal = potVal + 1                         ' increment count
  LOOP
  RETURN

Update: If using the P1T on the OUTH group (P8..P15) as recommended, DO NOT use this code -- use RCTIME as you normally would with the P15 SETUP jumper moved to the DN position.

[ilusion]

We are in fact looking at relocating the 5 VDC caps (for filtering when servos are connected) so that the Prop-1 Trainer can be used on P0..P7 pins.  Typically, however, we would use it on the upper group as P14 has a SETUP jumper which corresponds to the button input circuit on the Prop-1 Trainer.

Cool :) I like playing with the prop-1 trainer board. its a neat way to keep from having to lug a corpse around with you when you're trying to test triggering! ;) I've been playing with the Prop-2 this morning have have been sucessful in getting it to work as expected using this bit of code:


' {$STAMP BS2}
' {$PBASIC 2.5}

' Prop-1 trainer board demo
' Adjustable speed chaser with button reverse

RC         PIN     15    'Define where the POT is located
Button1    PIN     14    'Define where the pushbutton switch is

Pressed    CON     1

cntI       VAR     Nib   'used for counter
result     VAR     Word  'holds POT caluclation result
First      VAR     Nib   'Hold the first LED in the chase
Last       VAR     Nib   'Holds the last LED in the chase


MAIN:
  IF Button1 = Pressed THEN ' Check for the button
    First = 13               ' set the start LED # high
    Last  = 8                ' set the ending LED # low
  ELSE
    First = 8                ' set the start LED # low
    Last  = 13               ' set the ending LED # high
  ENDIF

  FOR cntI = First TO Last

    HIGH RC              ' charge the cap
    PAUSE 1              ' for 1 ms
    RCTIME RC, 1, result ' measure RC discharge time

    HIGH cntI            'Light the LED
    PAUSE result         'Use the POT derived value to determine the ON time
    LOW cntI             'Tunr off the LED
    PAUSE result         'Use the POT derived value to determine the OFF time

  NEXT

GOTO MAIN


This allows you to adjust the speed of the chasing and to use the button to reverse the direction of the chase. I've noticed that if I "flag" the jumper for P15 (to replicate the instruction in the prop-1 trainer description for Prop-1 use) that the pot no longer seems to work. Is this what you were referring to as the circuit being designed differently for BS-1 use?

Vern

[JonnyMac]

You need to remove the SETUP jumper from any pin that use the POT (Prop-1) or RCTIME (Prop-2) instructions as the jumper holds the pin at a specific level and will not let the cap (the C in RC) charge or discharge.

[ilusion]

You need to remove the SETUP jumper from any pin that use the POT (Prop-1) or RCTIME (Prop-2) instructions as the jumper holds the pin at a specific level and will not let the cap (the C in RC) charge or discharge.

huh. Thats weird, using the code I posted above, it does not work unless I have the P15 jumper in the "DN" position. If I remove the jumper, it no longer returns any value other than "0" across the entire range of sweep. If I put the jump in the "UP" position, I get nothing but zero across the sweep as well. However, if I place the jumper in the "DN" position, I get a sweep from 0 to 284...? I think I'm gunna try the code you put up Jon... see if I get different results...

Vern

[JonnyMac]

I take it back, Vern, you're right.  You see, the RCTIME function requires a parallel RC circuit and by adding the SETUP pull-down (DN) resistor, you've provided a discharge path for the cap.  Don't use my manual code -- it has horrible resolution; use RCTIME.

Code Select Expand

READ_POT:
  HIGH PotPin
  PAUSE 1
  RCTIME PotPin, 1, result
  RETURN

Where "PotPin" is 15 and "result" is a word variable.  On my Prop-2 I got results of 1 to 310 with the P1T pot.